This invention relates generally to stabilized earthen structures, and specifically relates to an adjustable turnbuckle style assembly for connecting precast concrete panels to a previously constructed wire face wall, which has been or may be subjected to foundation settlement.
Retaining wall structures may be comprised of backfill or earth material with a facing of precast panels. Mechanically stabilized earth structures are generally described in a series of Vidal patents including U.S. Pat. Nos. 3,421,326, 3,686,873, 4,045,965, and 4,116,010.
Vidal disclosed that longitudinal, tensile members positioned within a granular, compacted mass of earth to thereby enhance the coherency of the particles that form the mass. The stabilized soil mass can then serve as a wall or embankment. This phenomenon of enhanced coherency is accomplished, at least in part, by frictional engagement of particles in the mass with the tensile members or tie strips extending through the mass. Often such stabilized earthen mass includes a facing made from precast concrete panels.
A variety of methods and apparatus are known for attaching the tensile members projecting from the stabilized earthen mass to the precast concrete panels. For example, U.S. Pat. No. 4,961,673, issued to Pagano, discloses a connector that attaches a mounting plate, extending from the back face of a panel to a tie strip extending from within the stabilized soil mass. The attachment is achieved by threading a bolt through the opening in both the tie strip and the mounting plate and securing the bolt with a nut. The Pagano arrangement permits little adjustability with regard to horizontal and vertical offsets of the panel connectors vis-à-vis the tiestrips when installed.
U.S. Pat. No. 5,971,669, issued to Crigler, discloses a connector that permits some horizontal and vertical adjustments at the attachment points of the precast concrete panels and the tensile strips of the mechanically stabilized earth structure. The Crigler connection has a two-part housing, i.e., there are two, separate female connectors that threadably receive the male turnbuckle through the open end of the housing. The connection attaches the wire mesh panels that define a face for the stabilized soil mass, to precast concrete facing panels. The attachment at the panel facing is made by means of an elongate member oriented substantially parallel to the ground level that passes through the aperture at the end of the first housing as well as apertures that extend from the face of the precast concrete panels. The apertures are lined up, and the elongate member is passed through the series of apertures to secure the connector. The connection at the precast concrete panel wall, however, allows movement in the longitudinal direction of the member between the apertures.
When constructing an earth retaining wall of the type described, the granular material, which is compacted for cooperation with the tensile members, may not fully consolidate to its final volume during the period of wall construction. For example, compacted earth may only consolidate approximately 90% of its expected bulk consolidation during the construction phase of such a retaining wall. Over time, the bulk form may therefore continue to consolidate and, as a result, differential settlement may occur between the soil mass and the precast panel facing.
Due not only to the difficulties inherent in predicting differential settlement, but also to general variations in construction tolerances, the connecting points between the precast concrete panels and a previously constructed wire face wall may not line up in directly opposing positions. In this event, some vertical and horizontal offset between the connecting points may necessarily result.
The present invention is a low-cost connector assembly that efficiently allows for significant differential settlement between precast concrete facing panels and the mechanically stabilized earth mass without transferring undue stress to the wall panels. The invention is an adjustable assembly that connects fixed points on the face of the precast concrete panels to the wire mesh wall that can accommodate significant offsets between connection points. The universal joint connections allow the connector assemblies to be rotated such that the connection points in the closest proximity can be linked. The invention provides a plurality of connectors where the ends are pivotally connected at fixed spaced pivot points to accommodate misalignment by forming angled rather than straight connections, which in combination defines a three-dimensional truss. The ends of each connector define a first array at the facing panels and a second array at the connection of the connector to the stabilized earth structure such as to a wire mesh facing. These and other objectives, advantages, and features of the invention will be set forth in the detailed description which follows.